In recent years, organic EL display devices having organic EL elements have been broadly used as displays of mobile phones and TV sets, etc. Organic EL elements, each having a structure of a first electrode, an organic EL layer, and a second electrode formed on top of another in this order on a substrate, have received attention as light emitting elements capable of low-voltage direct-current drive. For formation of an organic EL layer, generally known are methods of forming an organic layer by a vacuum evaporation technique using a shadow mask (e.g., Patent Document 1), by an ink jet technique, and by a transfer technique with laser irradiation. Among these techniques, use of the transfer technique is preferable when an organic layer is to be formed by high-definition patterning even for a large-size panel.
Examples of the formation method of an organic layer by the transfer technique include a laser transfer method and a method using a lamp.
In the laser transfer method, a donor substrate including a light heat converting layer and an organic layer formed on the entire substrate surface and a transfer target substrate on which an organic layer is to be formed are used. The two substrates are opposed to each other, and regions corresponding to organic layer formation regions are irradiated with laser light. The portions of the organic layer in the laser-irradiated regions sublimate and adhere to the transfer target substrate, whereby the organic layer is formed by transfer (see Patent Document 2, for example).
Patent Documents 3 and 4 disclose formation methods of an organic layer where a donor substrate is opposed to a transfer target substrate via a transfer mask, to form an organic layer by transfer. In these methods, the donor substrate and the transfer mask are placed one upon the other with a given spacing therebetween.